alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Trojan Cridex checkin"; flow:established,to_server; content:"POST"; http_method; content:"/mx5/B/in/"; http_uri; reference:url,blog.webroot.com/2012/07/13/spamvertised-american-airlines-themed-emails-lead-to-black-hole-exploit-kit/; reference:url,stopmalvertising.com/rootkits/analysis-of-cridex.html; classtype:command-and-control; sid:2015546; rev:5; metadata:created_at 2012_07_31, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)